Manufacture of brominated blue indigo dyestuffs.



' ALBRECHT SCHMIDT. HEINRICH MAI'N, GERMANY, ASSIG- 1\TORS T FARBWERKE VORM. MEISTER LUCIUS &

1,043,463. No Drawing. 1 Original application filed December 17,1907, Serial N 0. 406,946. Divided and this application I To all whom it'may concern: f

.1 IT STATES Parana ornion.

or HocHsnon-rHn-MAIN. GERMANY,A CORPORATION or GERMANY.

RossNER, AND HANS EAL-HORN, 0F HocHsr-oN-Tim- MANUFACTURE oFBRoMI'nA'rEn BLUE/INDIGO DYESTUFFS. i

Specification of Letters Patent.

Patented Nov: 5,- 19 12.

f fi1ed'J'anuary 29,- 1909, genial No. 475,073. Renewed July 26, 1912. Serial No. 711,729.

' Be it known that we, ALBRECHT SCHMIDT,

Ph. D., HEINRIonRossNER, Ph... D., and

' ish-black pei'bromid in the following mani Hans BALHonn, Ph. D., citizens of the E'm-- p'ire of Germany,res1d1ng at Hchsbon-the- Main, Germany, hayeinyented certain new and useful Improvements in the Manufacture of Brominated Blue Indigo Dyestuffs, of which the following is a specification.

This application is a division of application Ser. N 0. 406,946, filed Dec. 1.7, 1907.

We have found that when the greenishblack products (perbromids) manufactured at raised temperature inconcentrated sulfuric acid or monohydrate according to Eir-v amples II and III of the U. S. Patent- 918 .920. application Ser. No. 406,946, are

treated with a bisulfite solution or other a-gents, capable-ofeliminating bromin, blue brou'iinated indigo dyestuffs are obtained.

which contain a percentage of. halogen cor.-

responding to at least 4-. atoms of halogen. The dyeings produced by means of these i'ly-cstutis on cotton in .the hydrosulfit'e- Vat are characterized by their shades having a remarkable green hue.. which are specially apparent when seen 1n artificial light.

Example 1: Dibroinindigoobtained for instance by brominationof indigo -is' converted. according to theprocess described in the U. S. Patent 918.920.1nto the greenner: 1. part of dibromindigo is introduced into 4.-10 parts of monohydrate or concentrated sulfuric acid while stirring andwell v cooling. during which operation it is advantageous for the better distribution 2'. e. conversion of the indigo to grind the mass for some time in the ball-mill; then 1.5 parts of br-omi'n 'are'run iniwhile cooling and stirring and the temperature raised up to about wh1le well stirring or grlndlng, which temperature" is inaintalned for some hours.

Thereupon the stirring of the mass is continned focseveral hours atordinary ternperature. The product of the process described in the U. S, Patent 918.920 separates as 'a' greenish-black mass (perbromid). For isolating this mass it can be filtered from the sulfuric acid and finally pressed out between clay and asbestos. Now, 10 parts of this product or the reaction mass itself are poured into 10 parts of a concentrated biquote solution which has been diluted with ice, whereupon the blue dyestutf separates,

in the form of blue flakes and is then isolated by filtration. This dyestuff after being dried turns into 'a violet-blue powder which is soluble in concentrated sulfuricfacid with a blue color. This product" contains about 55 to 58% of bromin and .dyes in the hydrosulfite vat cot-ton a considerably greener blue tint than the tetrabroniindigo claimed in ..U. S.-.Patent No. 856.776, a fact which is especially apparent in artificial light.

' If instead of the dibromiiidigo, the dichlo-rindigo claimed in U; Patent No. 812,598 be used, which latter may be pre: pared for instance by chlorinating indigo, a dyestufi' is obtained which dyes quite similar tints and which besides chlorin also contains bromin. In the'place of the bisulfite also other agents capable of eliminating bromin may be employed; for instance-the greenish-black products may be heated-While passing air through the mass, whereby the perbromid volatilizes.

Example II: 10 parts of the greenishblack reaction product which is obtained according 'to Example I from dibromindigo (or dichlorindigo) by means of monohygets split and the free bromin' ldrate or concentrated sulfuric acid, and;

which is used either directly as such or preferably after being filtered from'the excess of sulfuric acid. are poured into a solution. previously prepared with ice. of 15 parts of sodium hydrosulfite and 20 parts of concentrated bisulfite solution while stirring. "After the. formation of sulfuric acid has ceased the grayish-green product thereby obtained is filtered off. it shows the following properties: It dissolves in concentrated sulfuric acid with a dirty olive-green color. in alkali hydrate with a yellowish-brown color: it dyes cotton in alkaline solution clear blue tints. which especially when seen in artificial light show a green hue. V Having now particularly described our invention what we claim is: p

1. The herein described process otinaking blue hrominated indigo dyestuffs. containing at least four atoms of halogen. which consists in treating with agents. capr'ile of eliminating bromin. the greenislrhlack bro.- minated products from' dihalogen indigos ontai'n'ing at least five atoms of halogen,

being soluble in highly concentrated sulfuric acid, and turning blue when mixed with water and bisulfite.

2. As new products, the blue broniinated indigo dyestufi s containing more halogen than a tetrahalogen indigo, said dyestufi's being soluble in concentrated sulfuric acid with a. greenish-blue color, yielding by treatment with nitric acid in glacial acetic acid a oroduct from which 5-7 dibroinisatin melting at 249-250 C. may be isolated, and dye- 7 ing in the hydrosulfite vat cotton clearblue tints which, especially when seen in arti ficial light,'show a green hue.

'3. As new products, the grayish-green leuco compounds from theblue brominated indigo-dyestuffs containing more halogen than a tet-rahalogen indigo; said leuco compounds being insoluble in water, soluble in alkali-hydrate solution with a yellowishbrown color, yielding by treatment with nitric acid in glacial acetic acid a product from which 5-7 dibromisatin melting at 249- 250 C. maybe isolated, and dyeing in an alkaline hydrate solution cotton and wool blue tints.

In testimony, that weclaim the foregoing as our invention, we have signed our names in presence of two subscribing witnesses.

ALBRECHT SQHMIDT. HEINRICH ROSSNER. I HANS BALHORN. YVitnesses:

JEAN GRUND, CARL GRUND. 

